A heater is object that emits heat to the suroundings or causes another object to achieve a higher temperature. In a household or domestic setting, heaters are usually appliances whose purpose is to generate heating. An electric heater converts electrical energy heat. Common applications include space heating, cooking, water heating and industrial processes.
The heating element inside every electric heater is simply an electrical resistor, and works on the principle of Joule heating: an electric current through a resistor converts electrical energy into heat energy. Alternatively, a heat pump uses an electric motor to drive a refrigeration cycle, drawing heat from a source such as the ground or outside air and directing it into the space to be warmed. Some systems can be reversed so that the interior space is cooled and the heat is discharged outside or into the ground. Heat pumps can deliver two or three units of heating energy for every unit of electricity purchased.